Purchasers of industrial scale water pumping systems (e.g., cities, municipalities, water districts) compare proposed pumping systems based not only on price, but also performance. That is, even for two proposed pumping systems from two different suppliers having the same purchase price, the long term cost of the systems may be significantly different, based on parameters such as electric motor efficiency and pump efficiency.
In some cases, overall efficiency of a pump and electric motor combination may be theoretically determined by mathematically combining standard pump information for the pump (e.g., pump “curves” that relate parameters such as head pressure, flow rate, and revolutions per minute (RPM) of the pump) with standard electric motor information (e.g., information that relates motor speed, torque, electrical efficiency). However, the standard information in most cases applies to a model of pump, not a specific pump. Likewise, the standard electric motor information applies to a model of electric motor, not a specific electric motor. Because of variations in the manufacturing process, actual pump performance and actual motor performance varies from the standard information. Thus, better information regarding performance is gathered when performance of the specific pump is measured, and likewise better information is gathered when performance of the specific electric motor is measured. Simultaneous measurement of performance of the specific pump coupled to the specific motor may provide the best overall information.
However, for vertical shaft submersible pump packages, where both the pump and the electric motor are designed for operation submersed in water and with their respective rotors held in a vertical orientation, combined performance testing in the designed operational configuration has not, to date, been achievable.